temperature: The property of abody or region of space that determineswhether or not there will be anet flow of heat into it or out of itfrom a neighbouring body or regionand in which direction (if any) theheat will flow. If there is no heat flowthe bodies or regions are said to be inthermodynamic equilibrium and atthe same temperature. If there is aflow of heat, the direction of the flowis from the body or region of highertemperature. Broadly, there are twomethods of quantifying this property.The empirical method is to taketwo or more reproducible temperature-dependent events and assignfixed points on a scale of values tothese events. For example, the Celsiustemperature scale uses the freezingpoint and boiling point of wateras the two fixed points, assigns the values 0 and 100 to them, respectively,and divides the scale betweenthem into 100 degrees. This methodis serviceable for many practical purposes(see temperature scales), butlacking a theoretical basis it is awkwardto use in many scientific contexts.
